1. Field of the Invention
This invention relates to a cloth piece supply machine and method in which cloth pieces for front flies of such trousers such as denim pants are conveyed successively in stack to, for example, a continuous slide fastener chain and are picked up one by one from the top of the stack, without being damaged, and the cloth pieces, with front faces facing in the same direction, are then supplied to, for example, a sewing machine, thus enabling a high-speed feed of cloth pieces.
2. Description of the Related Art
In attaching successive cloth pieces to a continuous slide fastener chain, it is necessary to supply the cloth pieces one in one or two seconds to meet the modern high-speed sewing machine. For this purpose, a large quantity of cloth pieces must be always previously stocked in a cloth piece supply station. However, since forty to fifty cloth pieces are supplied but in a minute, it is extremely difficult to stock in a single position a necessary quantity of cloth pieces to be processed in the working time.
To cope with this, a solution has been proposed, in which several tens cloth pieces in stack is placed in each of a number of cloth piece support portions arranged in a circle on a rotary disc, the rotary disc is intermittently rotated to move the individual support portion to the cloth piece supply position, whereupon the cloth pieces are picked up one by one from the top of the stack in the support portion and are successively supplied to a sewing station. When all the cloth pieces of one stack in the support portion has been supplied up, the rotary disc is rotated again to move the next support portion to the cloth piece supply position. While the rotary disc is thus in rotation, a new stack of cloth pieces is placed he on the individual emptied support portion.
In this kind of cloth piece pick-up apparatus, the cloth pieces are picked up by peeling one by one from the stack in the cloth piece supply position, and are then supplied to the next or sewing station. At that time, if even a single cloth piece cannot be picked up or more than one cloth piece is picked up at once, the whole machine has to be stopped in the worst case so that the working rate would be lowered to create wastage, thus causing an increased cost of production. To this end, following methods have been proposed in an effort to reliably pick up the cloth pieces one by one.
According to one conventional pick-up method disclosed in, for example, Japanese Patent Laid-Open Publication No. HEI 1-221196, a pair of front and back rollers are used to pick up the vertically stacked cloth pieces one after another from the top of the stack. Each roller has a number of catch needles projecting from the circumferential surface and arranged in a row parallel to the axis of the roller. In operation, the two rollers are lowered to press against the front face of the cloth piece and, at the same time, are rotated through a predetermined angle so as to pull the cloth piece, whereupon the cloth piece as kept hooked on the two rollers is fed to a predetermined position where the two rollers are rotated reversely to release the cloth piece.
According to another conventional pick-up method disclosed in, for example, Japanese Patent Publication No. SHO 63-28635, a pick-up mechanism is situated in front of the horizontally stacked cloth pieces to pick up the cloth pieces one by one from the front side of the stack. In this conventional method, a roller rotatably supported on the end of a pivoting plate pivotally movable about its one long side cooperates with a claw projecting perpendicularly from an inner portion of the plate to pick up only the frontmost cloth piece. Further, U.S. Pat. No. 3,685,471 discloses a pick-up mechanism which activated two shuttles synchronously to separate a cloth piece from the succeeding cloth pieces and catched the separated cloth piece by a pawl movable back and forth horizontally along the front face of the cloth piece to feed it sideways.
What to be noted in connection with this kind of cloth piece supply station is that the cloth pieces must be rearranged in such a manner that front faces face in the same direction, before being fed to the next station. This problem is inevitable as long as it is intended to stack the successive cloth pieces efficiently. It has currently been a common practice to fold a continuous strip of cloth in a zig-zag pattern and then to cut the cloth strip into a predetermined shape of cloth pieces. Consequently, front faces of every other cloth pieces of the stack faces inversely; if the thus stacked cloth pieces are fed one after another to the next station, the successive cloth pieces will be received in that station necessarily with front faces facing up and down alternately. In order to place all cloth pieces with front faces facing in the same direction, a means for placing the successive cloth pieces with front faces facing in the same direction must be situated in the cloth piece feed path.
Japanese Patent Publication No. SHO 63-28635 and U.S. Pat. No. 3,685,471 disclose a means for detecting the direction in which one face of the individual cloth piece being faces and then rearranging the successive cloth pieces in such a manner that front faces face in the same direction. Especially in U.S. Pat. No. 3,685,471, a means for inverting the cloth piece is disclosed in detail, according to the description of which the picked up cloth piece is fed the gap between a pair of parallel endless belts and, at the same time, when the cloth piece is discriminated necessary to be inverted, the front end of the pair of endless belts is angularly moved by 180.degree. to twist the endless belts so that front faces of the successive cloth pieces will face in the same direction as they are fed by the endless belts.
However, in the conventional cloth piece supply machine in which the cloth piece stacks are arranged in one circle on the rotary disc, the distance between adjacent cloth piece stacks progressively increases toward the peripheral edge remote from the center the disc. In order to arrange as many cloth piece stacks as possible in one circle on the rotary disc to reduce the frequency of supplying new cloth pieces to cope with high-speed operation, it is inevitable to increase the diameter of the rotary disc so that no effective use of space can be achieved.
Further, in this kind of cloth piece supply machine, in order to pick up the cloth pieces reliably, it is advisable that the cloth piece to be picked up next should exist in a predetermined pick-up position, irrespective of whether the cloth piece is to be picked up from the top or side of the stack, depending on the vertical or horizontal stack.
In the cloth piece pick-up method disclosed in Japanese Patent Laid-Open Publication No. HEI 1-221196, partly since the cloth piece caught by the two rollers is tensed unnecessarily and tends to have a rent, and partly since the two rollers repeat three actions of catching, feeding and releasing the cloth piece, it is difficult to follow high-speed operation of the sewing machine.
In the cloth piece pick-up method disclosed in Japanese Patent Publication No. SHO 63-28635 and U.S. Pat. No. 3,685,471, the cloth pieces are stacked horizontally in the cloth piece supply station. Generally in this kind of cloth piece processing machine, the cloth piece assumes a horizontal posture while being processed in the processing station. Consequently, it is necessary to change the posture of the cloth piece from vertical to horizontal until the cloth piece reaches the processing station. This means that another action is added to the operation of the feed apparatus so that it would be made complex in mechanism and it would also be difficult to cope with the high-speed operation. Further, in the case where the cloth pieces are stacked horizontally, it requires an additional mechanism in order to maintain the posture of the cloth pieces to be picked up, which makes the entire mechanism much more complex.
With the cloth piece feed apparatus disclosed in U.S. Pat. No. 3,685,471, since the horizontally stacked cloth pieces is picked up one by one from the front side of the stack by the pick-up apparatus, the picked up cloth piece is fed forwardly in a vertical plane so that it will be supplied to the space between a pair of endless belts wound on two rotary shafts situated parallel to each other in the vertical plane. Therefore, if the front faces of the cloth pieces are to face in the same direction, the discharge end of the belts are twisted by 180.degree. at maximum so that the front faces of the cloth pieces can face in the same direction.
In the case where the cloth piece inverting and feeding means disclosed in the above-mentioned U.S. Patent is to be incorporated using the method in which the vertically stacked cloth pieces are picked up one by one from the top of the stack, it is necessary to angularly move the discharge ends of the belts by 360.degree. to twist the belts in order to invert the cloth piece being supplied in a horizontal posture, so that the belts cannot be driven and it would be very difficult to secure a timed operation. It is therefore impossible to apply the cloth piece inverting and feeding method, in which the cloth piece is twisted, to the method in which the vertically stacked cloth pieces are to be picked up one by one from the top of the stack, without reconstruction.